Publication details
Time-resolved cryo-EM visualizes ribosomal translocation with EF-G and GTP
| Authors | |
|---|---|
| Year of publication | 2021 |
| Type | Article in Periodical |
| Magazine / Source | Nature Communications |
| MU Faculty or unit | |
| Citation | |
| web | https://www.nature.com/articles/s41467-021-27415-0 |
| Doi | http://dx.doi.org/10.1038/s41467-021-27415-0 |
| Keywords | ELONGATION-FACTOR-GTRANSFER-RNA TRANSLOCATIONCONFORMATIONAL-CHANGESINTERSUBUNIT MOVEMENTINTERMEDIATE STATESCRYSTAL-STRUCTURESTRUCTURAL BASISHYBRID STATE80S RIBOSOMEHYDROLYSIS |
| Description | During translation, a conserved GTPase elongation factor-EF-G in bacteria or eEF2 in eukaryotes-translocates tRNA and mRNA through the ribosome. EF-G has been proposed to act as a flexible motor that propels tRNA and mRNA movement, as a rigid pawl that biases unidirectional translocation resulting from ribosome rearrangements, or by various combinations of motor- and pawl-like mechanisms. Using time-resolved cryo-EM, we visualized GTP-catalyzed translocation without inhibitors, capturing elusive structures of ribosome.EF-G intermediates at near-atomic resolution. Prior to translocation, EF-G binds near peptidyl-tRNA, while the rotated 30S subunit stabilizes the EF-G GTPase center. Reverse 30S rotation releases Pi and translocates peptidyl-tRNA and EF-G by similar to 20 angstrom. An additional 4-angstrom translocation initiates EF-G dissociation from a transient ribosome state with highly swiveled 30S head. The structures visualize how nearly rigid EF-G rectifies inherent and spontaneous ribosomal dynamics into tRNA-mRNA translocation, whereas GTP hydrolysis and Pi release drive EF-G dissociation. |
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